I can not decide

I have a complete game design and I am on my way to develop the game.
I am going to use OpenGL for the 3D graphics.
All the tutorials I saw use "GLUT" but I read that it is not good for professional or commercial use because it is old and not supported any more.

So, I decided to use cocoa to manage the the OpenGLView.

I know C, objective-c and little bit C++.
The game is Desktop game and if I will manage to release it I will consider Iphone and Ipad too.

My question is: Should I develop the game entirely on Objective-C + OpenGL(which will work on Apple machine only and it will not be cross platform) or Should I use Cocoa just for managing window, keyboard and mouse and the game itself will be written in C (or C++ if it is better).

If you think I should use "GLUT" I will be more than glad if you say why?

Any comments will help me to decide, tutorials on objective c + OpenGL will be great too (not Apple ones) or tutorials which include Objective-c and C to work with OpenGL.

What is more important to you, supporting Windows and Linux or supporting iPhone and iPad? Objective-C and OpenGL gives you Mac, iPhone, and iPad support.

If you want to support Windows and Linux, I recommend using a cross-platform game library like SDL, SFML, or Allegro. I have not used SFML or Allegro, but with SDL, you can use SDL to create a window, handle events, and read user input and use OpenGL to draw. I am not sure how well SDL, SFML, and Allegro support iPhone and iPad.

If you decide to use SDL, you can read a tutorial on using SDL with OpenGL by clicking the link in my signature.